


Sensei

by MeisterEule



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Ecto-Penis, Ecto-Tongue, Ecto-Vagina, I love tagging, Inspired by Fanart, M/M, Not Beta Read, Plot What Plot/Porn Without Plot, Porn, Smut, Underfell Papyrus, Underfell Sans
Language: English
Status: Completed
Published: 2016-03-25
Updated: 2016-03-25
Packaged: 2018-05-29 01:21:39
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,584
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6353287
Author URL: https://archiveofourown.org/users/MeisterEule/pseuds/MeisterEule
Summary: <blockquote class="userstuff">
              <p>Underfell Universe </p>
<p>Sans lost a bet to his younger brother, but he didn't thought of such a 'prize' that Papyrus want from him. </p>
<p>Smut and stupid stuff inside - sorry for the good summary!</p>
            </blockquote>





	Sensei

**Author's Note:**

> Waaaah!! This is a fanfiction inspired by the awesome and amazing art of eli-sin-g from tumblr! 
> 
> (( WATCH THIS:: http://eli-sin-g.tumblr.com/post/140839217883/sanspais-are-thirsty-kouhais-favorites )) 
> 
> I love the art and needed to write something about it~ also it's a little thing I did for my 110 follower special ! ~~ hope all the dearies on my tumblr like it, tho.   
> Have fun with this little smut! ~

“What's this suppose to mean?“ Sans gazed over his opponent, who only shake his head. A grin formed on his face of the younger skeleton, he had a bag in his hands, want to give it to Sans.

 

“I suppose you forget what kind of day it is today and what you should do for me dear brother” he held out the paper bag inviting. The shorter one accepted it hesitantly, the red circles looked suspiciously inside it before a deep red blush spread over his cheekbones.

 

“Th-that... you fucking otaku!” anger build inside him, he looked at Papyrus' face whose grin became even wider. The younger one sat on the chair of his desk, his legs crossed, he was wearing a black suit underneath the jacket Sans could see a white shirt. He also wore a tie. Papyrus seemed to be really serious about this.

 

“You should better get yourself dressed, otherwise this would have been the good chance you've missed. Or do you want to break your promise?”   
Sans gritted his teeth, hold back another anime-related offense, he would go unheeded anyway.

 

Why did he only make this stupid bet in first place and why the hell did he lost it in the end?   
Sans should have known, as he was sitting in front of the TV with Papyrus a few days ago, that he couldn't win a bet against his brother.

 

Only a few times Papyrus would make a bet and from the point in which he had entered the bet Sans should have been knowing that he would lose it. Each bet with the younger one, even if it were only four or five, he lost everyone to him.

 

Unsure he was still starring into the small bag in his had before he heard a loud cough and he slightly jerked.

 

“And?”

 

“I'll be right back” with these words he left his brother alone and disappeared into his own room and closed the door behind him.

The skeleton knew that he would lose even the little rest of his dignity.

 

Sans wanted to open the door to the room of the younger as he remembered the small piece of paper inside the paper bag and faltered. Why did he made this stupid mistake and lost the bet against his little sadistic brother?

The hand moving from the doorknob against the wood, he took a deep breath – even if he had no lungs, his breath was short – slowly and carefully he knocked on the door.

 

“Come on in.”

 

Hesitantly he opened the door, entered the room and closed the door behind him. Papyrus turned around in his chair, looking at his brother with a broad grin on his face as he gazed over his brother in the clothing that he had given to him.

 

“B-Boss-”

 

“What was that?” the furious glace sends a cold shiver down his spine, unsure he turned his head to the side, pulled with one hand on the short skirt he wore.

 

“S-Sensei” the red on his cheeks grew darker, he felt the intense gaze of the taller one and kept trying to pull the skirt down a bit more.

 

“Come here, you surly want to be a good student, are you?” Papyurs' voice was nothing more than a whisper, again it sends a shiver down Sans' spine, with slow steps he walked over and stopped in front of the chair his brother was sitting on.

 

“You do not need to be shy, you look absolutely beautiful Sans” again the blush grew darker, with embarrassment the little red balls looked into the face of the skeleton on the chair. One of Papyrus' hands founds his way onto the waist of the smaller one, he pulled him closer, forcing him to sit on his lap.

 

Reflexively one of Sans' hand land on one of the shoulders of his opponent, the other one laid down on his chest, which was hiding under the white shirt and the black jacket. Still he could clearly hear the fast beating of his soul, it seemed that the winner enjoyed his prize.

 

“You are so awful quite, what's the matter?” the hand on Sans' hip decided to discover the one on top of him, it found it's way under the fabric of his blouse. At the sudden and unexpected touch the 'student' jerked slightly, he closed his eyes and breathed haltingly.

 

Determined the eager hand sought a way under the waistband of the skirt, the grin on his face grew wider as he realized that the little skeleton was more into this whole game as he wanted to admit it.

 

“Hmm... what a naughty little girl. You sit on your teacher's lap without any underwear?” his hand went forward, stroking slightly over the pelvic bone of the shorter one and elicited a small gasp.

 

“Sensei... I-I” Sans didn't want to wear the underwear his brother put in the bag because he wanted to keep a bit of his dignity to himself. His whole appearance made him incredibly uncomfortable – he wore a way to short blue skirt, black knee socks and to make a matching school uniform he also wore a white blouse with a big blue ribbon. At least Papyrus was so kind to give him a light brown jacket he could take over the blouse with the big ribbon.

 

“What were you going to say?” slowly and teasingly one finger stroked over his pelvic, he felt the slight twitching of the other. Also he could feel the grip on his shoulder become stronger before Sans was starting to wiggle on his lap.

 

“Pretty excited, are we? But before you'll have all the fun I want you to do something for me, my sweet little girl” a whimper left the throat of the humiliated skeleton. Why did he liked it to be called 'little girl' in that outfit?

Gently pushing his older brother back, off from his lap, the elder caught himself on shaky legs before he slumped to the ground. Eagerly the red balls in the dark eye sockets watched his 'teacher' which opened his dark pants with a short flick and freed his erection from the narrow fabric.

The elder swallowed audible, the circle in his eyes turned into little hearts as looked at the large member of the other one.

 

“Hmm... I think you know what do to, right?” the monster on the chair spread his legs wider to give Sans more space between them.

Without another word the shorter skeleton fell onto his knees, took his place between the long legs of the taller one and put a hand on the magical dick.

Sans opened his mouth, let his conjured tongue came out, leaned down further and licked over the entire length, before the red tongue played around the tip.

 

“God... if you were so good in other things too Sans” the comment caused the smaller to growl in response, again he licked teasingly over the entire length.

 

“Hmm, Sensei, you taste so good” this little game Papyrus was playing – Sans could play it too. Slowly he leaned down even further over his cock before he took it completely into his mouth. Without wanting to wait any longer or to tease him even more he moved his head up and down, brought his tongue to work too.

 

“Look at me” the deep voice sent a hot shiver through his bones, the red hearts looked up into the broad grin of his brother. On his cheekbones was a slight red blush. Apparently Papyrus seemed to be loved the role play they were doing too. Sans would never to this again.

 

The quiet but steadily sounds that grew louder inspired him to become faster and more intense in his movements, he broke away completely after a few minutes, leaving a fine track of salvia on his cheek before he licked over his own teeth.

 

“I think you have earned you a reward” Papyrus leaned forward, putting his right hand on Sans' cheek, pulling him closer to himself before he brought his own tongue out of his mouth.

The red hearts became larger as the student was aware of what was happening next. Each of his bones began to shake, he also brought back the tongue that magically formed, the hearts watching as his younger brother came closer before he took property of what was his.

 

Searching for any support the elder grabbed the shoulders of his opponent, replied the even mire intensely expectant kiss as best as he could, but he had no chance against the dominance of his younger brother. Whimpering Sans pressed himself closer to the larger, he wanted more, needed more of his touch.

 

Astride he was sitting on the left leg of his brother, his eyes squeezed shut and enjoying the intense feeling. He felt a hand was laying on hi back and pulled him even closer. Sans didn't noticed that they were turning on the chair, not until his back was pushed against the table edge.

 

Papyrus broke the kiss, observed the image on his lap incisively and had to grin.

He had never thought that his bigger brother would look so damn sexy and erotic in these clothes – the reddened cheekbones and the hearts in his eyes that looked at him desperately reinforced his desire to use him even more.

 

“Sans, you sure want to make your teacher happy, aren't you?” the immediate response was a weak nod, his mouth slightly open Sans leaned forward to lick at the cheek of the other monster.

 

“Everything for you Sensei” the elder was amazed by himself that he could sound so calm, though he was about so explode. In the next moment he felt two hands that lift him and put him on the edge of the desk.

  
“Then be a good girl and create something suitable for me, okay?” his words made the addressee melt away. A small gasp left his throat, in the next moment the younger one lifted the skirt and watched what his brother had made for him.

 

“Hmm.... and you are already so wet down there, even if I haven't touched you yet. You seem to like the whole thing more than you want to admit it. I wonder how you taste Sans” he leaned forward, his tongue licked playfully over the wetness of the other, eliciting a loud groan from the shorter one.

 

“Hnn... S-Sensei” to stifle any further sound he laid his left hand over his mouth, whimpering he struggled to stay upright. The other hand landed on the shoulder of his teacher who was giving him a reward of what he had done to him a few minutes ago.

 

“You taste amazing” the praise made him going crazy. The taller skeleton had hardly done anything and he was about to reach his orgasm.

 

“S-Sensei... I-I” desperately Sans gripped the fabric stronger, focusing not to give in to the strong feeling building up in his chest. His legs were pressed further apart, he felt the skillful tongue entered him and coaxed him another long moan.

  
“Hm, come if you want” amused Papyrus noticed that the legs of his student began to tremble strongly, also the grip on his shoulder tightened as he entered him again with his tongue, deeper than before.

 

“A-Ah... oh s-stars” Sans threw his head back as his orgasm was taken over him, reflexively he clenched his legs as far as possible with the skeleton between them and whimpered loudly when he dropped down onto the wood.

Heavy he drew air through his nose, he took the hand of his brothers shoulders over his own eyes. For a moment silence filled the room, before the older one felt the tongue of his brother again, wanting to continue and causing him to jerk strongly.

 

“B-b-boss” it was not possible for him to thing straight and to address the taller right when he felt overwhelmed by strong feeling and pleasure. The over stimulation would kill him.

 

With a smacking sound Papyrus left his place, licking over his teeth and looked up to the monster above him. Sans gasped quietly, with one eye he looked down, meeting the others gaze.

 

“I think you just forgot how you should speak to me my sweet little girl, but do not worry, in a few moment you'll be screaming my name” with his mouth slightly open and small red hearts in his eye sockets the shorter skeleton was watching as Papyrus leaned over him. A few seconds later his dick pressed against the wet entrance, teasingly he didn't move, earning a loud whimper from the one underneath him. Desperately Sans pressed himself further down, caused the tip to entered him.

 

“Aaah... m-more, p-please” Sans wanted to continue pressing himself against the others cock, but after his first attempt he was held down. Painfully slowly the younger pressed himself inside his brother, inch by inch. The monster on the table panted hart, putting his head back in his neck and his hands grabbing the edge of the table.

 

“God, you're so tight. Normally I would simply break you, but... we should do this more often” when he entirely sunk into the smaller Papyrus gasped quietly, his gaze rested in the face of his student. It demanded a lot of control not to thrust into him as usual, instead he retreated slowly before pulling out and forcing himself inside again, more faster this time. For his action he earned a loud groan, as well Sans tried to meet each of his thrust.

 

“P-Paps... p-please” the red hearts stared at the ceiling, his mind was blank, he couldn't concentrate longer on the role play, he needed relief from his brother, now.

 

“Sans” the rough voice send a cold shiver down his spine, whimpering he took in the voice of the other monster as it began to take a faster pace.

Every thrust was commented by Sans with a groan, whimper or Papyrus' name leaving his throat, the intense feeling in him grew bigger, the faster the other moved.

 

“Paps... haaah I I'm c-close” the red tongue hung out between his teeth, salvia ran down his cheek which was licked away immediately by the other skeleton.

  
“Come for me Sans” greedy the younger kissed his brother, who returned it weakly and clumsy. Again Papyrus stepped up the pace and the force with which he was thrusting inside his smaller brother, bringing him over the edge the second time today, with Papyrus' name leaving his throat.

 

A few moments later the taller one gasped loudly and gritted his teeth as he buried himself deep inside Sans and reached his orgasm. Heavy breathing and small gasp filled the room, the elder one felt the head of his younger brother putting on his chest. One of his own hands went down and gently stroking the head on his chest.

 

“I think we should make this more often” after both has returned from their high they looked into each others eyes, the red on the cheeks of the cross dressed monster became darker again.

 

“Th-thats... what you wish! Forget all off this! It will never happen again!” slowly straightened from the wood Sans kept himself atop of the table and watched his brother angrily.

 

“I think that you will consider it again, but at first you can wash the clothes, you got it all messy” the grin on Papyrus' face came back, causing the other one to curse.

 

**This stupid Otaku!**

 


End file.
